namespace MvcAppPersianDatePicker.ViewModels
{
    public class PostViewModel
    {
        public Post post { get; set; }
    }
}

namespace MvcAppPersianDatePicker.Controllers
{
    public class HomeController : Controller
    {
        [HttpGet]
        public ActionResult Index()
        {
            var model = new PostViewModel();
            model.post = new Post() { AddDate = DateTime.Now.AddDays(-1), Title = "تست" };
            return View(model);
        }

        [HttpPost]
        public ActionResult Index(PostViewModel model)
        {
            if (ModelState.IsValid)
            {
                // todo: save data
                return RedirectToAction("Index");
            }

            return View(model);
        }
    }
}